[Vadim Finkov] “sound quality of AC3 is just as good as Dolby E if not better”
You clearly don’t know about the difference in data rate between ac3 files & Dolby E.
I was at the digital broadcast conference in Jackson, Wyoming over 12 years ago when the rep from Dolby announced the development of Dolby E. He explained the reason for the development was to enable Dolby digital data to be embedded in a 48Khz PCM data stream which you could not do reliably with ac3.
As well as running FCP for online & grading I also run a sound studio so I can tell you I have enough experience of sound deliverables and formats on nearly 800 broadcast programs to tell you again that what you are trying to do is not a deliverable standard and not recommended by Dolby or Sony.
If you want to store your 5.1 mix with the HDCam tape, then burn the PCM files to a DVDRom and put it inside the tape box.